Vol.4,No.2,2024-Table of Contents
- OPEN ACCESS ARTICLE
- Experimental evaluation on the axial crushing performance of BFRP-bamboo winding composite hollow components
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000053 Online published:2024-9-7
- Abstract In order to study the quasi-static axial crushing performance of BFRP-bamboo winding composite hollow components, considering the cloth ratio of BFRP (0%~14.68%) the number of BFRP layers (0 layer~4 layers) as an influencing factor, 20 tube specimens were designed for quasi-static compression tests. In this paper, the failure modes of the specimens under quasi-static axial compressive load are presented with the relevant load-displacement curves. The deformation types were carefully studied to evaluate the compressive crushing indicators of the specimens. The test results showed that when the cloth ratio of BFRP increased from 0 to 14.68%, the specific energy absorption (SEA), the mean crushing force (MCF) and the crushing load efficiency (CFE) increased to some extent, whilst the initial peak crushing force (PCF) did not show any trend. When compared with those of the bamboo winding hollow components (BT), the SEA, MCF and CFE of BFRP-bamboo winding composite hollow components with four layers of BFRP winding outside of BT (BBT4) increased by 87.53%, 194.37% and 255.59% respectively. Compared with other composite hollow components such as composite wrapped hollow components (CWT) and carbon reinforced composite hollow components (CRCT), BFRP-bamboo winding composite hollow components (BBT) showed superior crushing resistance while offering the advantages of light weight.… More
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- The influence of nucleus dates waste and ceramic wastes in sustainable concrete
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000048 Online published:2024-9-4
- Abstract Recycling has progressed recently, turning specific non-renewable resources into renewable ones. This has led to a considerable increase in research on using waste materials such as ceramic and nucleus date waste as alternative aggregate materials in buildings. They suggest using aggregate from nucleus dates rubbish and ceramic waste to reduce the amount of waste in the environment and address material shortages at building sites. This study was aimed at determining whether the incorporation of ceramic waste aggregates (CWA) and nucleus dates aggregate (NDA) instead of coarse aggregate can improve strength ultra-high-performance concrete (SHPC) properties. Ten SEC combinations were prepared: 10%, 20%, and 30% of NDA, CWA, or a combination of both. After testing, quartz powder (Q.P) or silica fume (S.F.) can increase the UHPC by enhancing its mechanical characteristics. Waste as construction materials could have substantial technological, economic, and environmental advantages when employed within a sustainable development framework. The study's conclusions proved that replacing NDA or CWA can improve the qualities of SHPC, especially when replacing 10% of the original material.… More
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- Life cycle assessment and mechanical strength of cement composites with conventional, and recycled fine aggregate
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000052 Online published:2024-9-3
- Abstract Generally, sand as a filler material in the concrete composite is mined from the riverbed, which is the primary source of the entailed fine aggregate to keep pace with the emergent demand for concrete production. Unbridled sand extraction from the riverbed and the river bank has detrimental impacts on the environment and river geomorphology. On the other hand, construction and demolition sites generate a significant amount of solid waste, which contains fine aggregate. This study aims to explore the applicability of recycled fine aggregate (RFA) in comparison to coarse sand and fine sand in cement composites, considering their compressive strength, financial aspect, and environmental sustainability by means of Life Cycle Assessment (LCA). Hence, 12 (twelve) different combinations of the aforementioned fine aggregates were taken into consideration to determine the extent of using RFA as a replacement for conventional fine aggregates, signifying the motivation of the study. In this study, the crushing strength of cement mortars at different curing ages was compared. At 28 days, mortar with 100% coarse sand showed 25% higher, and mortar with 100% fine sand showed 67% lower compressive strength than the mortar with 100% RFA. The mix combination of 25% RFA and 75% coarse sand produced the cement mortar with a maximum compressive strength of 48.25 MPa. From LCA, subsuming the waste product (RFA) into cement composite exhibited the lowest environmental impact, in contrast to those made with natural sand. Considering the physical properties of fine aggregates, and the crushing strength of mortar along with environmental and economic aspects, cement mortar with RFA can be an environmentally sustainable option and an approach to reduce construction waste and expenses.… More
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- Flexural behavior of high-strength reinforced concrete beam with hybrid fiber under normal and high temperature
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000051 Online published:2024-9-3
- Abstract The low cost of basalt and steel fibers makes their use in enhancing concrete properties very attractive, this paper presents experimental research on the use of Basalt Fibers (BF) and Steel Fibers (SF) and their effect on compressive, tensile, and flexural behavior of reinforced concrete beams under normal and elevated temperatures. Nineteen beams, 114 cubes, and 114 cylinders were tested to find the optimum percentage of fibers. The percentages of BF used were 1%, 2%, and 3.5% by cement weight, while the percentages of SF were 0%, 0.5%, 1%, and 1.5%. Heated samples were subjected to 600 ℃ for 3 hours and left to cool off naturally before testing. The test results show that using BF and SF significantly increased the tensile strength of unheated cylinders, with the optimum fiber content of 1% BF - 1.5% SF achieving an increase of 163% over the control. For heated cylinders, the optimum fiber content was (2% BF - 1.5% SF) achieving an increase of 175%. For compressive strength, enhancement was more modest for most of the fiber content ratios used, and the optimum mix of (1% BF - 1% SF) achieved an enhancement for unheated and heated conditions of 27% and 44%, respectively. Flexural results show that beams employing a mix of 2% BF and 1% SF yielded the most favorable result at normal temperature, enhancing the capacity by 27% compared to the control. While at high temperatures, using an optimum mix of 1% BF and 1.5% SF achieved a 27.2% increase compared to control. The use of BF and SF in concrete has also been proven to increase the ductility of the beams and has moved the failure mode from shear to flexural failure.… More
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- Integration of fly ash and ground granulated blast furnace slag into palm oil fuel ash based geopolymer concrete: a review
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000050 Online published:2024-9-3
- Abstract The construction industry significantly depends on concrete due to its mechanical attributes and economy efficiency. The increase demand for building materials, particularly concrete, has resulted in overproduction of ordinary portland cement (OPC) and consequent significant release of carbon dioxide (CO2) into the atmosphere. For addressing these issues, alternative innovative and sustainable materials, such as geopolymer concrete, which utilised waste materials as binding agents have been introduced, leading to a reduction in CO2 emissions. Palm oil fuel ash (POFA) contains abundant silicates and aluminates, making it well-suited for use as binder in geopolymer concrete. On the other hand, POFA geopolymer concrete with high volume exhibits reduced early strength development, decreased workability, and an extended setting time. Therefore, this review paper emphasizes the need of including fly ash (FA) and ground granulated blast furnace slag (GGBS) into POFA-based geopolymer concrete. A notable result of the review is that the inclusion of aluminium oxide and iron(III) oxide in FA improves the chloride binding capability, resulting to a dense microstructure with high strength. In addition, the presence of calcium oxide in FA and GGBS enhances the creation of C-S-H, N-A-S-H, and C-A-S-H gels, resulting in a decrease in porosity and an enhancement of the fresh and mechanical characteristics. Furthermore, the use of FA improves the insulation and thermal efficiency of the geopolymer concrete. Therefore, integration of FA and GGBS in POFA geopolymer may enhanced the mechanical and durability qualities. Further study is required to optimize the composition of POFA, FA and GGBS in the mix, and researching new, cost-effective alkaline activators obtained from waste products offers another avenue for boosting the efficiency of geopolymer synthesis.… More
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- A new constitutive model for recycled aggregate concrete cylinders actively confined with post-tensioned metal straps
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000049 Online published:2024-9-3
- Abstract The compressive strength of cylindrical columns of recycled aggregate concrete (RAC) is lower than that of equivalent normal concrete columns. Active confinement can recover some of such lower compressive strength, but limited research has examined the stress-strain behaviour of RAC cylinders with active confinement. This study proposes a new constitutive model for RAC cylinders actively confined with post-tensioned metal straps (PTMS). Using pneumatic tools, the PTMS technique involves applying a post-tensioning force to high-strength metal straps. RAC cylinders (⌀150×300 mm) with different confinement ratios (ρv = 0, 0.35, 0.52, 0.80 or 1.6) were subjected to axial compression tests to determine their maximum strength and axial strains. The RAC was produced using recycled concrete aggregate (RCA) as coarse aggregate, considering three compressive strengths: 15, 21 and 24 MPa. The test results indicate significant increases in strength and axial strains as the confinement ratio increased, with the strength improving by 29% to 196% and peak axial strains by 90% to 158% across ρv values from 0.35 to 1.6. Based on the test results and a regression analysis, a new stress-strain constitutive model is proposed to assess the effectiveness of the PTMS confinement. The results of this study promote the use of RAC in construction by demonstrating that the mechanical properties of RAC structural members can be effectively enhanced through the PTMS technique.… More
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- Design and construction of houses with Guadua cane and rice husk in Ecuador as an alternative to local development
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000047 Online published:2024-9-3
- Abstract The use of sustainable construction materials as a response to habitat problems is one of the urgent alternatives for Ecuador. The country has a high production of rice, an intensive crop that generates a high volume of polluting waste that is not efficiently managed, which causes damage to the environment. The purpose of the research was the design and construction of a construction system with the joint use of Guadua cane, of ancestral domain, and rice husk as components of a hybrid lightweight concrete. As a result, two houses were built in 1992 and 2020, respectively, validating the feasibility of the proposal. A flexible, resistant, sustainable system is achieved, which takes advantage of local resources, both traditional and alternative, that allow to give an answer to the habitat with a good aesthetic finish. It is an alternative for the local development of autonomous governments that allows the construction of decent, durable and comfortable housing, with the use of their own resources and in accordance with the country's traditions.… More
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- Investigating crack growth in two-dimensional plates with openings using the peri-dynamic method
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000046 Online published:2024-9-3
- Abstract Analyzing and simulating the growth of dynamic cracks in the shell of structures and two-dimensional plates is one of the important topics for providing solutions to prevent crack growth and sudden failures, which increases the lifespan of the structure. Despite many studies by researchers regarding the behavior of structures against crack growth and sudden failure, there are still many problems regarding the analysis and simulation of the mechanical behavior of shells and plates with openings. Therefore, the peri-dynamic method can be directly used to model crack growth in these types of structures. In this research, modeling of dynamic crack growth as well as factors affecting crack growth and branching in the shell of structures (with and without openings) were investigated using the peri-dynamic method in LAMMPS software. Then the results obtained from the pre-dynamic method were verified with the results of other methods. The comparison of different results showed that the peri-dynamics method is capable of properly modeling crack growth in plates and shells with openings, and in other words, this theory can predict the path of crack growth with high accuracy. According to the obtained results, it can be stated that the process of crack growth and branching in the shell of structures depends on values such as the applied stress, the type of material and the direction of the fibers in the composites, as well as the absence of openings in the shell, which by changing these factors, the speed and The path of crack growth in the body of the structure changes.… More
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- Effect of short basalt fibers on energy-dissipating properties of lightweight rubberized concrete shear wall
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000045 Online published:2024-9-3
- Abstract To enhance the dynamic performance of shear walls, fine-grained rubberized basalt fiber concrete has been proposed as an alternative to conventional concrete. This is a promising material, yet the existing literature lacks an in-depth analysis of its energy dissipation properties. A comprehensive study was performed of fine-grained 100 x 100 mm cylindrical rubberized concrete specimens, both with and without basalt fibers, under low-cycle compression fatigue. The first concrete mixture had a volume fraction of 10 % crumb rubber, and the second concrete mixture contained a volume fraction of 0.3 % basalt fiber in addition to 10% crumb rubber. Scanning electron microscopy and computer tomography were used to validate the material's inner structure, adhesion, crumb rubber and basalt fiber distribution. To acquire the mechanical and dynamic properties of the material, hysteresis loops were obtained from 1000 cycles of compression fatigue tests under 0.1 and 0.05 strain rates on a servo-hydraulic machine through quasi-static laboratory tests. The obtained concrete properties were incorporated into VUMAT plasticity model of concrete and imported to ABAQUS for seismic analysis of reinforced concrete shear walls. A cyclic pushover analysis of the shear wall has been conducted to characterize its hysteretic behavior and energy dissipation for two consecutive concrete series, predicting long-term seismic performance. The concrete series with basalt fiber exhibited higher seismic resilience with hysteretic damping of 9.3% compared to 8.7% for the series without basalt fibers.… More
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- Development and performance evaluation of sustainable lightweight geopolymer based fireproofing coatings for steel construction
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000044 Online published:2024-9-3
- Abstract This study developed a novel, sustainable, lightweight, and high-ductility fireproofing coating using granulated blast furnace slag (GBFS), fly ash microspheres (FAC), alkali activator, and polyethylene (PE) fiber as raw materials. The critical mixing ratios of FAC to GBFS (4:6), the water-to-binder ratio (0.55), and the alkali activator modulus (1.4) were determined to meet the requirements for fluidity, compressive strength, and flexural strength. The residual strength and thermal stability of the sample were evaluated through high-temperature exposure tests. The compressive strength results showed that even at 900℃, the lightweight geopolymer-based fireproofing coating exhibited 23 MPa as compared to that of 61 MPa at room temperature, which is 30% of its room temperature strength. X-ray diffraction and scanning electron microscopy were carried out to examine the micro-morphology of the samples, revealing that the main component of the geopolymer was Ca2(Al2SiO7) in a colloidal state at 30℃, 300℃, and 600℃. The reduction in strength at this temperature range was mainly attributed to the surface crack extension. However, at 900℃, the gelatinous Ca2(Al2SiO7) underwent dehydration and transformed into crystalline Ca2(Al2SiO7), or zeolite. The interface bond performance between the fireproofing coating and the steel plate was thoroughly tested through direct shear and normal bond tests, using five different bonding techniques, as well as a tensile test on the fire-resistant material coated steel plate. The bond strength from direct shear test ranged from 0.05 MPa to 1.64 MPa and for normal shear test, the strength was in the range of 0.07 MPa to 1.43 MPa. The results of tensile strength test showed that the coating had high ductility and was fire-resistant, and it could deform synergistically with the steel plate, with a maximum tensile strain of 4%. These results demonstrate the coating's excellent deformation performance.… More
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